An important development in the field of public health is the emergence of behavioral health technologies and mobile health (mHealth) applications (apps). Recovery Record (RR) is a self-monitoring app that aims to enhance engagement in recovery for individuals with eating disorders (EDs), and has demonstrated wide appeal and reach over its 2-year period of prototype-testing. In line with the objectives of a Fast Track SBIR project, we aim to develop the prototype into an evidence-based adaptive intervention and test it against the current one-size-fits-all approach. RR's core functionality is eating and symptom self-monitoring, which preliminary data reported in this application suggests can facilitate a clinically meaningful reduction in symptoms in users with specific characteristics. The most potent predictor of symptom reduction is severity of cognitive distortions. The next step in app development and the first aim of our work program is to develop and pilot content that helps users challenge distorted thinking tailored to the needs of their symptom profile. In the second phase, we will randomize registered users of RR to receive either RR augmented with content tailored to their needs (RR-A), or RR in its current standard format (RR-S). We will test the efficacy of RR-A by comparing it to the standard product (RR-S). By the end of the study, the resultant high-quality evidence-based product will have commercial value. The overarching purpose of this study is to build on the success of RR-S and develop it into a high quality evidence based adaptive intervention (RR-A).